Analysis of human colon tumors and related materials will be accomplished to explore the potential value of retinoic acid-binding protein (RABP) as a biochemical marker of malignancy in clinical colon cancer. We will also determine the relationship between the appearance of RABP and of cellular retinol binding protein (CRBP) in tumorigenesis and also compare these with normal colon tissues. Separation of RABP and CRBP will be accomplished and specific antibodies will be produced against these two proteins. The elevated levels of RABP and CRBP in mouse colon segments after administration of 1,2-dimethylhydrazine will be determined, and will be evaluated with respect to the degree of preneoplastic and neoplastic developments.